Extreme heat costs women workers in poor countries over $57 billion yearly

A new report from HERA launched today during London Climate Action Week shows that extreme heat is becoming one of the biggest threats to economic growth worldwide. It heavily impacts city economies, overwhelms health systems, and hits women workers the hardest in a hotter world.

The report, Counting the Cost of Heat: The Case for Urgent Solutions for Cities, uses global and regional data. It focuses on four cities with different climates and heat issues: Ahmedabad in India, Bangkok in Thailand, Monterrey in Mexico, and Freetown in Sierra Leone. In these cities, heat already reduces city GDP by 4 to 8% each year and leads to over 1,000 deaths.

Globally, women in the informal sector are most affected. They lose about $57 billion in earnings each year due to extreme heat, representing 4-11% of their wages. Without action, these losses could increase three to five times by 2050 due to climate change, rapid urban growth, and aging populations.

"Extreme heat is draining growth, health, and equality, not a distant climate risk," said Kathy Baughman McLeod, CEO of HERA. "The evidence in this report is clear. Heat is hurting the women most exposed and least able to escape it, and it is damaging the economies of cities that can least afford it. But the same evidence shows us the way out. The solutions exist, they are affordable, and they work."

Heat impacts women’s health and earnings

The report shows that extreme heat does not affect everyone equally. Women, especially the 740 million working in the informal sector, face the highest risks and least protections.

Key findings include:

Informal sector women in every region except the US and Europe lose an estimated $57 billion annually due to extreme heat. Many of these women earn as little as $3 a day.

Heat causes more deaths among women than men, up to 20%. This is due to physical factors and social conditions that increase women's exposure and lower their ability to adapt.

The effects go beyond the individual. Women reinvest up to 90% of their earnings into their families and communities. When heat cuts their earnings, spending on children's education, food, and healthcare declines. In Bangkok, extreme heat reduces women's annual spending on their children by $500.

These losses have wider effects. In Bangkok, productivity losses from heat lower the city's GDP by an average of 4% a year, equal to the city government’s total budget, and as much as 8% in a very hot year. In Freetown, extreme heat increases the average household debt-to-income ratio by 3% each year, reducing investment in education and business.

In Monterrey, heat-related premature births are expected to more than triple over the next 25 years.

In the cities studied, women face annual productivity losses from heat ranging from about 3% in Monterrey to 11% in Bangkok. Since women generally earn less than men, 66% less in Freetown and 4% less in Bangkok, even small losses in productivity hit household income harder, leaving less to fall back on.

In these cities, working women are often more likely than men to work informally. In Freetown, up to 91% of employed women are in informal jobs, compared to 83% of employed men.

The danger continues at night

The report points out that rising nighttime temperatures, which are increasing faster than daytime highs in many cities, are a major cause of illness and death.

Hot nights offer no relief to the body, and together with heatwaves, they account for 85% of heat-related deaths. Lower-income residents living in homes made from heat-trapping materials like corrugated iron feel this most, especially in Freetown.

Cost-effective solutions available

Despite the seriousness of the threat, the report's main message is one of hope. A mix of low-cost actions, like Heat Response Plans, urban green spaces, cool roofs, labor protections, and heat insurance, could lower heat-related deaths by over 36% by 2050 in the cities studied.

These actions provide great value for money:

Heat Response Plans can return between 12 and 90 times their cost, making them some of the best public health investments available.

Cool roofs can lower indoor temperatures by 2 to 7°C (3.6 to 12.6°F) right after installation, helping low-income households at high risk indoors.

Heat-related income loss insurance for the poorest informal workers could cut earnings losses for women in the informal sector by over 40% by 2050.

The report emphasizes that these benefits depend on inclusive design. Many standard heat responses often miss those who need them most. Early warning systems rely on phone ownership and literacy. Cooling centers assume people can move freely and have spare time. Labor protections often overlook informal workers. Tailoring these actions to the needs of the most vulnerable helps protect them and ensures better returns on every dollar spent.

A global tool for change

The report comes with HERA’s first-of-its-kind tool, designed to help policymakers, practitioners, and development partners understand how extreme heat affects people and the economy. This global tool shows how heat impacts mortality and economic output in 11,408 cities across 190 countries, beyond the four cities in the report. It allows users to see how these impacts could change by 2050 and compare the costs and benefits of different adaptation methods.

The report includes the most thorough evidence to date about heat’s effects on women. It combines climate projections, health and labor productivity modeling, gender-specific economic analysis, and personal stories from informal women workers. It also highlights case studies showing how heat disrupts their sleep and spoils the goods they sell.

The report concludes with four urgent priorities: developing sustainable financing models, creating stronger partnerships across sectors and levels of government, investing in better evidence on how heat affects women, and raising awareness about heat literacy. The need for action is clear, and the time to build heat resilience is limited.